1. Field of the Invention
The present invention relates generally to a liquid oxygen storage and delivery system.
2. Description of the Background Art
Therapeutic oxygen is the delivery of relatively pure oxygen to a patient in order to ease pulmonary/respiratory problems. When a patient suffers from breathing problems, inhalation of oxygen may ensure that the patient is getting an adequate level of oxygen into his or her bloodstream.
Therapeutic oxygen may be warranted in cases where a patient suffers from a loss of lung capacity for some reason. Some medical conditions that may make oxygen necessary are chronic obstructive pulmonary disease (COPD) including asthma, emphysema, etc., as well as cystic fibrosis, lung cancer, lung injuries, and cardiovascular diseases, for example.
Related art practice has been to provide portable oxygen in two ways. In a first approach, compressed oxygen gas is provided in a pressure bottle, and the gas is output through a pressure regulator through a hose to the nostrils of the patient. The bottle is often wheeled so that the patient may be mobile. This is a fairly simple and portable arrangement.
The drawback of compressed, gaseous oxygen is that a full charge of a bottle that is portable does not last a desirable amount of time.
In order to get around this limitation, in a second approach a related art liquid oxygen (LOX) apparatus has been used wherein LOX is stored in a container and the gaseous oxygen formed from the LOX is inhaled by the patient.
The related art LOX apparatus enjoys a longer usable charge than the compressed gas apparatus for any given size and weight, but has its own drawbacks.
Related art LOX systems typically include a stationary storage container located in a patient's home and a portable unit that the patient uses outside the home. The stationary storage container must be periodically refilled with LOX by a distributor.
A significant percentage of the cost of having a LOX system is in the cost of frequent recharging trips by the LOX distributor. A distributor may have to make weekly recharge trips to a patient's home, or even more frequently, to recharge the patient's LOX system. There thus is a need in the art to cut deliveries or cut costs in other ways.
The main drawback of the related art is that considerable waste occurs. One source of waste is that prior art devices provide continuous flow. Also, in the related art, the portable unit may be filled with LOX and used for normal activities and movement. When the patient is done using the related art portable unit, remaining LOX left within the related art portable unit is vented, wasting any remaining oxygen. Because the LOX continues to convert to gaseous oxygen when not being withdrawn, venting is provided for in both the stationary and portable related art units. When the pressure in the related art stationary unit increases beyond a certain point (such as when the related art portable unit is being used), the related art stationary unit must be vented.
There remains a need in the art, therefore, for an improved LOX storage and delivery system, with less gas consumption and requiring fewer deliveries of LOX to the patients home.